Marine Weather and Tide Forecast for Sturgeon Bay, WI

DISCUSSION
Issued at 434 PM CDT Sun Apr 12 2026

Rain and thunderstorms from earlier today have exited to the east, however more development in southwest WI is tracking to the northeast. Initial indications showed this batch of rain just brushing the far southeast portion of the GRB forecast area, but current radar trends indicate this round of rain may impact the Fox Valley as well. Some lightning is also present, but do not expect any strong or severe storms. This round of rain/thunder will depart by mid to late evening.

A surface cold front drops south across WI on Monday, and then stalls out somewhere in central to southern WI. An initially capped environment during the afternoon will break down via increasing low level jet Monday evening, setting the stage for thunderstorm development. Initially individual cells will grow into a complex and progress eastward. MUCAPEs of 1000 to 2500 J/kg along with steep mid level lapse rates indicate mainly elevated storms with large hail (up to ~2") and damaging winds (~60 mph) as the main threats. However, any storm in proximity to the warm front could tap into some surface based instability resulting in a small tornado threat, mainly for central WI, but this will also depend on where the front stalls out. Heavy rain and localized flooding will also be a concern, with pwats of 1.0-1.4", and many rivers and soils already saturated from the recent wet pattern.
Best timing for severe potential is from 6PM Monday to 1AM Tuesday, which has trended slightly early with recent model runs.

Expect a lull late Monday night into Tuesday morning, but as the surface boundary will still be draped across WI more showers and thunderstorms are expected to develop along this feature Tuesday afternoon and evening. The severe threat is lower, but hail and damaging winds are possible, especially south of Hwy 29.

The pattern remains active Wednesday, as a surface low tracks along the front, and then finally pushes eastward Wednesday night. Severe thunderstorm potential will come down to the exact track of this low/location of the front, but at the moment remains low.

Deep upper trough tracks towards the Plains and Midwest Friday and this weekend, bringing more opportunities for rain, thunderstorms, and possibly even snow by Sunday.

Meanwhile, milder temperatures are expected through Friday with daily highs in the 60s and 70s. Readings return to near normal by this weekend.

AVIATION
for 00Z TAF Issuance Issued at 738 PM CDT Sun Apr 12 2026

Showers will continue across east-central WI this evening, mainly impacting MTW but clipping ATW/GRB for a time. Main issue will be gusty winds up to ~35 kts in/around the showers. A stray shower is also possible in far north-central WI late this evening, but no impacts are expected at RHI. The VFR/MVFR clouds are expected to lower to mainly MVFR/IFR later this evening and overnight, along with some fog which will reduce visibilities. The southwest winds should help keep the fog from becoming dense, but as winds diminish early Monday morning across central and north-central WI, some denser fog is possible, along with some LIFR ceilings.

During the mid-late morning on Monday, conditions will begin to improve as fog dissipates and clouds lift and/or scattered out.
Quiet weather is likely for the early-mid afternoon followed by thunderstorms, some likely strong to severe, Monday evening and overnight.

Winds will be SW through the evening, then gradually veer W overnight. Gust of 15 to 30 knots are expected at times tonight, locally higher near/in the showers. Lighter winds are expected on Monday, shifting to the south/southeast Monday afternoon.
Additionally, LLWS at 2kft will continue through early Monday morning due to a strong LLJ overhead.

HYDROLOGY
Issued at 434 PM CDT Sun Apr 12 2026

Additional rainfall from Monday through Wednesday is likely to be at least 1" (50-90% chance), but lower potential for more than 2" (10-30%). However, rain amounts will be highly variable based on where various rounds of convective storms track. Additional rain is expected late in the week and into the weekend, but it is too early to hone in on specific amounts.

Based on the most likely current forecast, minor flooding will continue on the Wolf River through the next week. Runoff from Upper Michigan along with additional rain will bring minor and moderate flooding on the Menominee River early this week, too.
Minor flooding is also ongoing or possible on other area rivers, with flood warnings currently out for the Oconto River and a small portion of the Wisconsin River.

GRB WATCHES/WARNINGS/ADVISORIES
None.